#include <stdio.h>

typedef unsigned char byte;

void show_bytes(void * start, size_t len){

  printf("%lu bytes from %p:", len, start);

  int i;
  for(i = 0; i < len; i++){
    printf(" %.2x", ((byte *) start)[i]);
  }
  printf("\n");

}

void memory_demo(){

  char s[16] = "Cecil Sagehen";
  show_bytes(&s,16);

  double d = 3.1415926535897931;
  show_bytes(&d, 8);

}

void shift_demo(){

  char temp = (char) (0x41 << 4); // cast truncates to one byte
  printf("0x41 << 4 = %.2x\n", temp);
  temp = 0x41 >> 4;
  printf("0x41 >> 4 = %.2x\n", temp);

  int temp2 =47 << 4;
  printf("47 << 4 = %d\n", temp2);
  temp2 = 47 >> 4;
  printf("47 >> 4 = %d\n", temp2);
  temp2 = -47 << 4;
  printf("-47 << 4 = %d\n", temp2);
  temp2 = -47 >> 4;
  printf("-47 >> 4 = %d\n", temp2);

}

void int_demo(){

  int x = 7;
  int y = x & 1;
  printf("%d & 1 = %d\n",x,y);

  x = -14;
  y = (x + 7) & 0xFFFFFFF8;
  printf("(%d + 7) & OxFFFFFFF8 = %d\n",x,y);

  void * p = &x;
  void * p2 = (void *) ((long)p & ~((long)0x3FF));
  void * p3 = (void *) (((long)p >> 10) << 10);
  printf("%p & ~0x3FF = %p\n",p,p2);
  printf("((%p >> 10) << 10) = %p\n",p,p3);

  void * p4 = (void *) ((long)p & ((long)0x3FF));
  printf("%p & 0x3FF = %p\n",p,p4);
}

int main()
{
  printf("Memory demo:\n");
  memory_demo();
  
  printf("\nShift demo:\n");
  shift_demo();
  
  printf("\nInt demo:\n");
  int_demo();

  return 0;
}